Pump or motor



F. BURGHAUSER PUMP OR MOTOR Filed April 14, 1938 l Patented Oct. 17, 1939 UNITED STATES PATENT OFFICE Application April 14, 1938, Serial' No. 202,068

Germany August 13, 1937 3 Claims.

' This invention relates to pumps or motors and more particularly to pumps or motors provided with screw-spindles and has forone of its prominent objects to provide an arrangement permit- B ting the screw-spindles being relieved from radial or transverse pressures arising during operation of the pump or motor by action of the operating liquid.

The present application is a continuation in part of my application for Letters Patent rof the United States, Serial No. 163,141, iiied September 9, 1937.

The aforesaid radial or transverse pressures exerted by action of the operating liquid onto the screw-spindles are ordinarily even in excess of the forces that are exerted by the operating liquid onto the screw-spindles in vaxial 'direction thereof.

In order to relieve the screw-spindles of pumps or motors of the present kind from said lastmentioned pressures or forces exerted in axial direction, special bores or the like have heretofore been provided in the casing of the pump or motor, said bores permitting the operating liquids being properly guided to counteract these pressures o r forces exerted in axial direction.

, However, according to the present practice the said radial or transverse forces or pressures have not received proper attention or even been regarded as an inevitable and inherent drawback,

although the friction arising'at the screw-spindles inthe casing of the pump or motor is frequently of such magnitude that, for instance, the pump or motor will not be able to start, which is due to the fact that the frictional moment due to the,axial pressures or forces is larger than the useful torque exerted on the spindles by action of the operating liquid.

According to my present invention, now the jo aforesaid radial pressures or forces arising in transverse direction of the screw-spindles of pumps or motors of the present kind due to the action of \the operating liquid are caused to be counteracted and suppressed in a simple manner 'E45 by providingy oppositely positioned bores in the casing that surroundsv saidv screw-spindles, said bores being connected with each other to communicate in pairs in a manner to provide a counteraction and equalization of pressures and to relieve the screw-spindles from said radial or tranverse pressures or forces. In consequence of this counteraction and equalization of pressures said'scrw-spindles willbe prevented from being pressed one-sidedly against the walls of the casing and, in addition, said radial or transverse (Cl. 10S-128) forces or pressures may be conveniently counteracted in a manner to either fully disappear or even come into .effect in reversed direction.

In the accompanying drawing which forms part of this specification, I have representedlsome ex- 5 amples of construction of a pump or motor with screw-spindles and the novel means for counteracting or suppressing th objectionable forces or pressures exerted on the screw-spindles.

In the drawing, Figs. 1 and 2 are longitudinal l0 sections, at right angles to each other, of a pump or motor having means for relieving the screwspindles solely from radial forces or pressures, While Figs. 3 and 4 are similar longitudinal sections through a pump or motor embodying com- 15 bined means for relieving the screw-spindles, both, from axial as well as from radial forces or pressures.

Referring more particularly to the drawing, the casing t ofthe pump or motor shownin the sev- 20 eral gures includes two properly co-operating screw-spindles, to Wit: a main screw-spindle a having a single thread and a side-spindle b having a double thread. Said side-spindle b is acted upon by a heavy pressure due to the operat- 25 ing liquid with the result that this spindle will be pressed in radial direction against the casing t.

In order to avoid and counteract or equalize this objectionable radial pressure there are provided at opposite points of the casing bores q, q', r, r', s 80 and s' communicating with each other in pairs, thus causing forces to be exerted on the screwspindles, said forces acting on one side as relieving and on the other side as loading forces on the spindles. 35

By arranging the'said bores in the manner indicated one-sided frlctlonal pressures between the spindles and the casing will be avoided to attain proper operation of the pump or motor.

'I'he operation of the pump or motor may fur- 40 ther be improved by providing, in addition to said cmeans for relieving the spindles from radial forces, further known means for relieving the spindles from axial forces, said latter means further serving to favorably act in opposition to the 45 bearing pressures, as indicated in Figs. 3 and 4 of the drawing. Relief from axial forces is effected by action of the operating liquid (pressure oil) iiowing from the pressure space u through the cylindrical gap of the bearing 1J and through 50 a longitudinal bore in the casing back into the suction space. Onthe one side the bearing will be relieved from pressure by action of a bore w leading to the suction space, while on the other side the bearing is directly under pressure from 55 the pressure space by way of a. bore m. 'I'he bearing in the suction space is arranged accordingly in sucha manner that the part of .the transverse thrust exerted thereon will be counteracted. By properly dimensioning the diameters of the bearings this arrangement will simultaneously serve to counteract the thrust exerted in axial direction onto the spindles.

The aforedescribed construction of the pump or motor with means for counteracting the transverse or radial forces or pressures exerted onto the spindles,'or with the combined means for counteracting,` both, the transverse or radial forces and the axial forces may principally be used with advantage with pumps or motors having screw-spindles of most different constructions, the pressure of-the operating liquid coming in every case into effect proportionately with the relieving forces. There will thus be the possibility of constructing pumps or motors operating with screw-spindles that will be fully relieved from forces acting between all operating members. In addition, pumps or motors constructed according to my invention do not require the use of special materials having high-grade running characteristics and consequently `cheap materials of lowergrade running characteristics may be used with advantage. At the same time the life-time of a pump or motor constructed according to my in- 'vention will practically be unlimited.

1. In a pump or motor, the combination of two cooperative screw-spindles, a casing substantially encompassing said screw-spindles with a running fit with the addendum of said spindles, and

means comprising opposite bores arranged in communicating pairs in said casing, connecting the area between the immediately adjacent surfaces of the addendum of at least one of said spindles and said casing on one side of said spindles with the corresponding area on the opposite side of said spindles, .for equalizing the pressure on opposite sides of saidrscrew-spndles, whereby the forces exerted on the spindles by the pressure of operating fluid between said adjacent surfaces faces of ythe addendum of at least one of saidv spindles and said casing on one side of said spindles with the corresponding area on the opposite side of said spindles, for equalizing the pressure on opposite sides of said screw-spindles, whereby the forces exerted on the spindles by the pressure of operating uid between said adjacent surfaces transverse to the axes of said spindles, are countransverse to the axes of said spindles, are counv teracted.

3. In a pump or motor, the combination of two cooperative screw-spindles, a casing substantialiy encompassing said screw-spindles with a running t with the addendum of said spindles, and means comprising opposite bores arranged in communicating pairs in said casing, connecting the area betweenthe immediately adjacent surfaces of the addendum of at least one of said spindles andsaid casing on one side of said spindles with the corresponding area on the opposite side of said spindles, for e'qualizing the pressure on opposite sides of said screw-spindles, whereby the forces exerted on the spindles by the pressure of' operating fluid between said adjacent surfaces transverse to the axes of said spindles, are coun-l ,teracted, bearings for said spindles, and means for relieving said bearings and therewith said spindles from'axial forces.

FRANZ BURGHAUSER. 

